In aviation, it is frequently necessary to drag bodies having arbitrary properties downstream of aircraft in flight. This can have various reasons. In the case of measurements of the atmosphere, for example, probes have to be dragged through the air in order to obtain meteorological data. Alternatively, in the case of tanker aircraft during flight, refueling pods with hoses are used to transfer, for example, fuel or water from a supply aircraft to another aircraft, which is to be supplied. In most cases, aircraft move through the air at very high velocities. Therefore, a turbulent slipstream arises downstream of the aircraft and of a body dragged by the aircraft. The properties of this slipstream depend on the construction shape of the bodies moved through the air. Herein, so-called streamlined construction types have a positive effect. Here, the design of the outer shape has the effect that the air vortices arising downstream of the body will turn out to be as weak as possible.
However, it is not always possible to use this advantageous shape. In the case of a refueling pod, for example, it must be possible to lead out a hose at the rear end of the refueling pod. For this purpose, an opening ensuring the exit of the hose and of its stabilizing cage has to be provided at this end. Therefore, the opening has a larger dimension, due to which a blunt construction shape is generated in the rear region of the refueling pod. In terms of fluidity, this shape has disadvantages, as vortices and turbulences, which can influence an object present in the slipstream and can deteriorate its stability, form downstream of such a blunt stream body.
If it is tried to operate a drag probe or a refueling hose downstream of a blunt stream body, an aerodynamic impulse on the dragged object is potentially generated by the turbulences, which unintentionally sets the object in motion.